Short-range wireless communication readers, such as Radio Frequency Identification (RFID) readers are becoming more prominent in a wide variety of mobile digital devices, such as cellular phones, personal digital assistants, pagers and other mobile terminals. The short-range communication readers provide the devices with the ability to communicate via RFID, Bluetooth®, infrared or other types of short range communication dependent upon the type of reader associated with the mobile terminal. Continuous active operation of the readers, however, consumes significant amounts of power. Therefore, in a typical mobile terminal with short-range communication capabilities the device is prone to require a larger power supply and/or more frequent charging of the power supply, as compared to the mobile terminal that is not equipped to communicate via a short-range communication medium. Both larger power supplies and more frequent power supply charging are not viable alternatives in the mobile environment. Larger power supplies lead to larger mobile terminals, which is counter-intuitive to the general mobile concept that “smaller is better” or at least more practical. In the same regard, frequent charging of the mobile terminal power supply is inconvenient for the user and reduces the lifetime expectancy of the power supply.
For example, a typical low frequency RFID reader runs on a 3 Hz scan cycle; meaning that it is activated, i.e., “wakes up”, once every 330 ms to check for transponders in the general vicinity. With current technology, this type of repetitive activation can add up to upwards of 20 percent of the power consumed by the mobile terminal. However, in the vast majority of instances the wake-up period results in no transponders being available, so that the power that is consumed is unwarranted.
In other instances, the signals that are detected pertain to an unsupported format or some other false detection. These unsupported formats and false detections further exacerbate problems related to power consumption because they trigger more frequent activation of the reader and in some instances further processing of the unsupported format to determine its incompatibility. As more short-range wireless communication systems are implemented using differing field strengths and differing operating distances they will in turn prompt more frequent triggering of the of the signal detection circuits, which start the systems auto triggering functions. This is because many of systems will have field strengths that could potentially set off RF detection systems that are intended to work only for short-range proximate communications. For example, as door access systems, “I code” or “EPC global” retail checkout systems or other systems having larger field radiation (i.e., stronger signals) become more commonplace they may trigger basic short-range communication detection systems, such as RFID readers and the like.
As such, there is a need in the industry to conserve the power in mobile terminals associated with short-range wireless communication readers to permit utilization of conventional power supplies and typical power supply charging schedules for the mobile terminals. Various attempts have been made to address power management in mobile terminals and, particularly those devices that are associated with short-range wireless communication readers.
One type of power-conserving method has been implemented for RFID short-range communication. The method involves limiting the “reading” of the identification RFID transponder, i.e., tag to only a portion of the tag, and if the RFID reader identifies that it has previously read the tag based upon the identification portion, the RFID reader does not read the rest of the tag. While this power-conserving method is helpful, the RFID reader still consumes more power than desired and the method does not address the problem of continual active operation.
In another recently developed power conservation method, an appropriate sensor measures the movement of the mobile terminal and active read operations continue while the movement of the device is unknown. When the movement of the device is identified, however, one or more of the subunits of the device is changed from an active operation mode to a sleep operation mode, where the sleep operation mode consumes less power than the active operation mode. The device then stays in the sleep operation mode while the movement of the device is known, and then changes back to the active operation mode when the movement of the device becomes unknown. Again, while this power-conserving method is helpful, the device still consumes more power than desired because the device is in an active operation mode anytime the movement is unknown, which amounts to most of the time that the device is in use due to the “mobile” nature of the device.
Thus, there is a need for techniques that permit greater conservation of power in mobile terminals associated with a short-range wireless communication transceiver/reader so that the mobile terminal does not need a larger power supply or frequent power supply charging. In particular a need exists to address the problems related to unwarranted power consumption related to a transceiver/reader that unnecessarily scans the proximate environment in instances in which the tags/transponders within the environment do not comply with the format supported by the transceiver/reader.